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[SteveFLHTK]

Ok, I have heard a lot of talk about "possible" crosstalk of O2 sensors created by removal of the cat's from 2010 and above bikes due to the location of the sensors.  Personally, I consider this akin to stories about Little Red Riding Hood and the 3 little pigs.  However, knowing a lot of people here have removed the cat's from their bikes....has anyone actually experienced this phenomena personally?  I don't want "I heard of" or "Someone told me" stories please.

[Doc 1]

Believe it....the bike will never run as good as it can with the Cat removed and the 02's cross talking....the VE's will be all over the place. I haven't just heard it I seen it, and proved it. Even with the cat in the front cylinder gets a little confused from the rear cylinder gasses, however the rear cylinder tunes very well. When the CAT is removed they both go wacky because you have MORE exhaust gas recirculation......it's not a myth.
  
Doc

[sadunbar]

However, there are some very good non-cat 2 into 1 into 2 "X" pipe options out there - that will not allow the 02 sensor cross talk...   

[SteveFLHTK]

Doc, you are one of the sources quoted as seeing crosstalk as a problem, I've just never had the opportunity for a direct communication with you before, and I have issues with hearing things like this third hand.  I've seen the inside of the pipe, and the rear sensor is in a pipe that extends several inches into the cat area (easily visible when it's removed).  The front sensor is basically at the beginning of the cat chamber.  I assume that the crosstalk is due to reversion of the gasses (please correct me if I'm wrong, as I said, it's an assumption).  I can visualize that there might be a possibility of the gasses backing up one way or the other at idle, but once you get on the throttle at all, the gasses are traveling at a pretty good velocity....how does some of the gas reverse with that much pressure against it?

I'm more of an electronics guy than a mechanic, so let me make a guess using that genre as an example.  When you have an antenna that's not properly tuned to it's transmitter, it will cause something called VSWR, which is basically power traveling against the primary flow, cutting down on true power to the antenna.  Is this a similar situation?  

[SteveFLHTK]

Sadunbar, I am aware of this....as a matter of fact I have one on my bike now.  My purpose for this post is not to make a decision for myself, but to prevent me from giving bad info to someone else, or, on the other hand, to allow me to give someone the correct info so they can make an informed decision.

[sadunbar]

Sadunbar, I am aware of this....as a matter of fact I have one on my bike now.  My purpose for this post is not to make a decision for myself, but to prevent me from giving bad info to someone else, or, on the other hand, to allow me to give someone the correct info so they can make an informed decision.

This is a quote from another site by Bob at RC Cycles....

"From info I have garnered from a couple MOCO tech guys I had the opportunity to speak with a few months ago:

The reason the 2010 FL bikes have cats is because the O2 sensors are now placed in a position (right before the cat can) that begs for exhaust crosstalk from the cat area. With the cat in place the exhaust is directed straight through to the tail pipes. Without the cat the exhaust just dumps into a can that promotes crosstalk/mixing.

This promotes closed loop system confusion due to mixed reading from exhaust crosstalk so the system will be working overtime to try to keep the AFR tied to the target. While it may be difficult to feel the confusion going on within the system, it's for sure there and will affect running. Whether the rider will be sensitive enough notice it or not is a question.

Not trying to start a pissing match about what actually happens, I'm simply reporting my findings from measuring, or trying to accurately measure, AFR from gutted cats on 2010 FLs."

[SteveFLHTK]

Only problem I have with that quote is that I thought the cat was added due to EPA requirements, not specifically because of the O2 sensor placement.

[sadunbar]

Only problem I have with that quote is that I thought the cat was added due to EPA requirements, not specifically because of the O2 sensor placement.

In 2009, only some headers had cat's.  The 2009 headers had the 02 placement near the heads - so crosstalk was no issue.  In 2010, the MOCO moved the 02 sensor location away from the heads (for other reasons) and near the collection can, where, as Bob mentions, crosstalk would be an issue.  Installing the cat in the header can in all FL bikes (starting in 2010) eliminated the issue of crosstalk.  So while the cat is necessary to meet the EPA requirements, the location of the cat also addresses the 02 sensor crosstalk issue.

[Doc 1]

Doc, you are one of the sources quoted as seeing crosstalk as a problem, I've just never had the opportunity for a direct communication with you before, and I have issues with hearing things like this third hand.  I've seen the inside of the pipe, and the rear sensor is in a pipe that extends several inches into the cat area (easily visible when it's removed).  The front sensor is basically at the beginning of the cat chamber.  I assume that the crosstalk is due to reversion of the gasses (please correct me if I'm wrong, as I said, it's an assumption).  I can visualize that there might be a possibility of the gasses backing up one way or the other at idle, but once you get on the throttle at all, the gasses are traveling at a pretty good velocity....how does some of the gas reverse with that much pressure against it?

I'm more of an electronics guy than a mechanic, so let me make a guess using that genre as an example.  When you have an antenna that's not properly tuned to it's transmitter, it will cause something called VSWR, which is basically power traveling against the primary flow, cutting down on true power to the antenna.  Is this a similar situation?  

Steve
No matter what rpm you are running there is always spent gasses or fresh air, depending on the length and diameter of the pipe, being moved up and down in the pipe with the exhaust pulses. At lower rpms it is more noticable however it does effect the 02 readings at higher rpm's too.
Get a ''X'' pipe from Fulsac or fuel moto....they work great and use the stock heat sheilds for that stock look. Bottom line is getting rid of the cat is getting rid of the header pipe totally.
Doc

[strokerjlk]

Ok, I have heard a lot of talk about "possible" crosstalk of O2 sensors created by removal of the cat's from 2010 and above bikes due to the location of the sensors.  Personally, I consider this akin to stories about Little Red Riding Hood and the 3 little pigs.  However, knowing a lot of people here have removed the cat's from their bikes....has anyone actually experienced this phenomena personally?  I don't want "I heard of" or "Someone told me" stories please.

I do them all the time. (stock head pipe cat removed) the pipe works very well actually once the cat is removed.
of course the sensors are bung plugs now,and the tune is all open loop. so cross talk dosent matter.
if you dont have to use the NB sensors to tune with, all's good.
you dont have to worry about being lean anywhere. you will give up a couple MPG.

[Doc 1]

I do them all the time. (stock head pipe cat removed) the pipe works very well actually once the cat is removed.
of course the sensors are bung plugs now,and the tune is all open loop. so cross talk doesn't matter.
if you don't have to use the NB sensors to tune with, all's good.
you don't have to worry about being lean anywhere. you will give up a couple MPG.

I don't know what you have against closed loop except I don't think you totally understand the concept. Running 02 sensors doesn't make the bike run lean....there is nothing wrong with the AFR being 14.2 to 14.5 in a no load situation, you gain nothing by running in the 13's with open loop.  Removing the 02 sensors is removing 1/3 of the ECM capability to maintain the target AFR that was requested in the tune that was done. Taking away the Adaptive Fuel Values is going backwards in the technology of today's fuel injection systems. Look,... the Vikings rowed a boat very well, however today we put motors on those boats....any one removing the 02 sensors because they don't like them or they are using the PC III or PCV is picking up the oars again.
The ECM will throw a code if it doesn't receive a signal from the 02's within 40 seconds, unless you install a resister in the 02 wire.
Doc

[SteveFLHTK]

Doc, I agree 100% about keeping closed loop active. Personally, I believe in working smart, not hard, so I plan on keeping that motor, unless you know of some Vikings I can hire cheap ;-)

That's one of the major gripes I had about the Power Commander. Why lose capabilities by disabling the sensors? Yes, the bike is too lean from the factory (thank you EPA), but if you're going to get a tuner, why not get one that works WITH the technology, not in spite of it.

[strokerjlk]

Your right nothing wrong with 14:2 afr. Where you come up with 13?
your wrong I understand it very well.
Vikings in 06 lol.
he asked a question and. I gave an answer. He dosent like the idea fine.
you don't like it fine. But don't assume I don't understand it.
someone else may see this and see it another way. 
If a guy has to tune a 2010 up with v tune or smarttune. Then he better fix the cross talk.
If you can tune or know a tuner that can tune without the fisher price toys.
there are other options.

[Razorback]

I don't know what you have against closed loop except I don't think you totally understand the concept. Running 02 sensors doesn't make the bike run lean....there is nothing wrong with the AFR being 14.2 to 14.5 in a no load situation, you gain nothing by running in the 13's with open loop.  Removing the 02 sensors is removing 1/3 of the ECM capability to maintain the target AFR that was requested in the tune that was done. Taking away the Adaptive Fuel Values is going backwards in the technology of today's fuel injection systems. Look,... the Vikings rowed a boat very well, however today we put motors on those boats....any one removing the 02 sensors because they don't like them or they are using the PC III or PCV is picking up the oars again.
The ECM will throw a code if it doesn't receive a signal from the 02's within 40 seconds, unless you install a resister in the 02 wire.
Doc

The 2010 models will not throw a cel light if you remove the sensors or sensor wires, it will read 02 sensor inactive if the ecm is read with a digital tech or twinscan etc.

[Steve Cole]

Different models within the same model year will get you different results if you disconnect the O2 sensors. Some will trip the light and some willnot but they ALL end up with a stored trouble codes in the ECM. Typically open loop tuned bikes run in the 40 - 43 mpg range and closed loop tuned bikes run in the 48 - 52 mpg range. We have 120R motors running closed loop just fine with the stock sensors and getting 48 mpg, while putting out 130+ HP, so I do not much see the need for going backwards and removing the O2 sensors. Some people still feel the need for carburetors too but that doesn't mean you need to put one on an EFI bike today to get it to run correctly.